Does anyone know a way to construct an intersection point between two parallel cylinders? Since pcdmis wants to use the center line of both cylinders and the centerlines do not intersect, the math fails. Is there a way to get the point where the two outside surfaces of the cylinders intersect?
intersection point
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wouldnt that create a line and not a point if the cylinders are tangent to each other or 2 lines if they overlap.
it is possible to do a workaournd using constructed features but need a bit more info
are you looking for the intersection point at a specific level of the cylinder? are you looking at the cylinders along the cylinder axis, so basically seeing 2 circles? or are you looking for a 3d point in space?sigpic

Create a plane perpendicular to the cylinders at one end, construct circles by intersection cylinderplane, create points by intersection circle1circle2 (and the other way around to get the other intersection point). Do all of that at the other end of the cylinders too, and you have what's needed to create the intersection lines. Do note that this will not reflect form errors in the cylinders  no real hits are involved.Last edited by AndersI; 09122019, 09:21 AM.AndersI
SW support  Hexagon Metrology Nordic AB
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Yes, a line would be great too. But I’ve tried that, and the math fails on that as well . I’m looking along the axis of the cylinders . So yes, basically 2 circles . So what I’m trying to do , is get the upper intersection point where the cylinders overlap. So say that is in my +X axis. In my X axis I have to get another symmetrical intersection point. Then I need to dimension the length between those two intersection points.
Thanks for the Reply.
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Well I’m talking about those two partial radiuses you see there in the picture. I was just measuring them as cylinders . If it would be easier to measure them both as circles I could do that. Try to imagine you’re looking right through that view and I’m measuring the circles or cylinders in the Z/X axis.
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the only radius i see is the one marked in red. the only intersections i see are the 2 lines marked in yellow
either way i'd intersect the line with the radius to create the intersection point to dimension from
the bottom intersection appears to be tangent which can cause the math fail issue if the part radius as machined isnt actually tangent to the line. then things start getting creative
realistically the radius location should be dimensioned to the radius center point not the intersetion/tangent point to other features
image_17503.jpgLast edited by mckenzie; 09122019, 10:09 AM.sigpic
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Originally posted by mckenzie View Postthe only radius i see is the one marked in red. the only intersections i see are the 2 lines marked in yellow
We'll have to wait for jefman's magic to solve this one…
Edit: Some links  https://www.analyzemath.com/CircleEq...pse_inter.html, http://yehar.com/blog/?p=2926 (this one is cool...)Last edited by AndersI; 09122019, 10:28 AM.AndersI
SW support  Hexagon Metrology Nordic AB
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im having a hard time wrapping my brain around the ellipse as a feature. if it was below the other geometry it would have hidden lines where it intersects thru the geometry and likewise if it was above the other geometry the ellipse would have some hidden lines. it looks like its just an ellipse drawn on the drawing. it's too early in the morning here, im confused

i love how we (qc folks) as a group tend to be the most confused group in the shop. the shop floor folks are never confused, ive watched them rapid the spindle z through the part, workholding and into the table with such confidence.
just for the record i was a machinist before i got smart and moved into the air conditioning


so just to make sure i understand the blue line is a shallow arc segment and your looking for the intersection of the blue arc and the red arc? if so thats going to be tricky pcdmis doesnt handle short arc segments very well. trying to extrapolate a circle from such a small section of the circle, any slight deviation in the arc will have a huge affect on the extrapolated circle diameter and location. usually when the engineers create stuff like this the 2 arcs are tangent so any little deviation in the features as machined and the arcs wont read as intersecting. im hesitant to suggest a work around because it will just be an approximation. what is the tolerance for the liner dimension youre trying to measure?
at a minimum i would treat them as 2d features and create 2 circles and start there.
image_17503.jpgsigpic
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The tolerance for the linear dimension is +/ .010. I know small circular segments never tend to read right . ESP when you have a tiny piece of a 29.667 diameter . I guess I’m not really concerned about the dimension coming in because the chances are slim, but more concerned about if there IS a way to theoretically do this in pcdmis. I’ve ran Into this multiple times and it’s driving me nuts . Haha
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Originally posted by Gagedude127 View PostThe tolerance for the linear dimension is +/ .010. I know small circular segments never tend to read right . ESP when you have a tiny piece of a 29.667 diameter . I guess I’m not really concerned about the dimension coming in because the chances are slim, but more concerned about if there IS a way to theoretically do this in pcdmis. I’ve ran Into this multiple times and it’s driving me nuts . HahaPcDmis 2015.1 SP10 CAD++
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